1. Field of the Invention
The invention relates to a vehicle that is driven by an electric motor, and a method of controlling the vehicle.
2. Description of Related Art
Vehicles that are driven by an electric motor, such as fuel cell vehicles and electric vehicles, are available in the related art (Japanese Patent Application Publication No. 2011-003278 (JP 2011-003278 A)). In these vehicles, a required torque of the electric motor is calculated in accordance with an accelerator depression amount, whereupon the electric motor is controlled such that an effective torque of the electric motor approaches the required torque.
In a typical torque characteristic of an electric motor, however, a torque output response is higher than that of an internal combustion engine, and therefore a rate at which the effective torque increases relative to the accelerator depression amount is high from a low speed. Hence, when a driver depresses an accelerator pedal at a low speed, a sensation of the vehicle shooting forward against the will of the driver may be generated. When the rate at which the effective torque increases relative to the accelerator depression amount is set to be small at all times, on the other hand, an acceleration feeling relative to the accelerator depression amount may deteriorate. As a result, there remains room for improvement in a method of determining the rate at which the effective torque increases relative to the accelerator depression amount.